T1ρ MRI and Discography Opening Pressure are Quantitative Biomarkers of Disc Degeneration In Vivo

INTRODUCTION –A quantitative assessment of disc health is essential for selection of treatment options and to the future of biomedical research in the development of new spine technologies. The Pfirrmann grade determined from T2 MRI is currently the gold standard to determine disc degeneration [1]. This method has been valuable for research, yet is extremely limited as it is not a continuous quantitative measure. Alternatively, T1ρMRI has been evaluated in the nucleus pulposus (NP) and correlates with the Pfirrmann grade, glycosaminoglycan (GAG) content, and NP mechanical properties in cadaver spines [2,3] and human subjects [4]. Provocative discography is an invasive test frequently used to determine if degenerative disc pathology observed using standard imaging is responsible for lower back pain symptoms. While somewhat controversial due to the subjective nature requiring the patient ́s pain response, there are several quantitative pressure measurements obtained as part of a manometric-controlled study. Opening Pressure (OP), pressure where injected fluid first overcomes the internal osmotic pressure and enters the disc, is a potential indicator of degeneration. The objective of this study is to evaluate T1ρ MRI as quantitative biomarker of disc degeneration in patients being treated for lower back pain (LBP) by comparing it to discography OP.